A shopkeeper expects a gain of 22.5% on his cost price. If in a week, his sale was of 392 Tk, what was his profit?

Question: A shopkeeper expects a gain of 22.5% on his cost price. If in a week, his sale was of 392 Tk, what was his profit?

Solution:
Given,
Selling price = 392 Tk
Cost price = (100/122.5) × 392 Tk
= (1000/1225) × 392 Tk
= 320 Tk

Therefore, Profit = 392 - 320 Tk
= 72 Tk